1. Field of the Invention
The present invention relates to an air conditioning system for a vehicle, and in particular to an air conditioning system mountable in the rear of a vehicle.
2. Description of the Related Art
A vehicle air conditioning system is mounted within the front of a vehicle, more particularly, within an instrumental panel.
Recently, an air conditioning system has been developed which comprises an integral unit including an evaporator and a heater core. The evaporator is a heat exchanger providing a cooling capability and the heater core is a heat exchanger providing a heating capability. Thereby, the system provides an improved space availability in the lower area or the foot area of a passenger compartment and also a reduction of the manufacturing cost.
Examples of the vehicle air conditioning system of the type having the integrated evaporator and heater core unit are disclosed in Japanese Patent Unexamined Publication Nos. 10-250344 and 10-250345.
The conventional air conditioning system disclosed in Japanese Patent Unexamined Publication No. 10-250345 will be explained with reference to FIG. 8. A conventional air conditioning system 50 includes a casing 50. In the casing 50, there are mounted an air inlet 54 for receiving intake air from the front portion of the vehicle and introducing the air into the system, an evaporator 56 for refrigerating or cooling the introduced air, and a heater core 58 located at the rear under side of the evaporator for heating the cooled air from the evaporator 56. A partition plate 60 is mounted at the rear portion of the heater core 58 in the casing 52. The partition plate 60 guides the air heated by the heater core 58 to a mixing area 62 located at the upper portion of the casing 52 where the heated air is mixed with the air cooled by the evaporator 56.
At the rear portion of the evaporator 56, there are provided a first damper 63 for controlling the rate of the air bypassing the heater core 58, and a second damper 76 for controlling the rate of the air flowing through the heater core 58. Thus, the rates of the cooled air and the heated air can be controlled. A foot passage 66 is provided between the partition plate 60 and a rear wall 52a of the casing 52.
A vent outlet 68 is provided near the mixing area 62 at the upper portion of the casing 52, a defrosting outlet 70 is provided in front of the vent outlet 68, and a foot outlet 72 is provided at the rear lower portion of the casing 52. These outlets 68, 70 and 72 are respectively provided with a vent damper 74, a defrosting damper 76 and a foot damper 78.
The conventional air conditioning system explained above controls openings of the five dampers 63, 64, 74, 76 and 78 so as to provide various modes such as a vent mode, a vent and foot mode, a foot mode, a foot and defrosting mode and a defrosting mode. The air having a desired temperature is discharged from the vent outlet 68, the defrosting outlet 70 and/or the foot outlet 72.
On the other hand, the air conditioning system for a vehicle requires, based on the functions of the outlets and comfortability of passengers, a relationship in which [air temperature of defrosting outlet (Tdef)] greater than [air temperature of foot outlet (Tfoot)] greater than [air temperature of vent outlet (Tvent)].
However, in the conventional air conditioning system 50 of FIG. 8, the defrosting outlet 76, the vent outlet 68 and the foot outlet 72 are provided along the casing 52 in turn from the evaporator 56 in the downstream area of the evaporator 53. Namely, the defrosting outlet 76 is the nearest of the these three outlets to the evaporator 56, the foot outlet 72 is the farthest from the evaporator 56 and the vent outlet 68 is located between the defrosting outlet 70 and the foot outlet 72.
Thus, the conventional air conditioning system 50 naturally has a relationship in which [air temperature of foot outlet (Tfoot)] greater than [air temperature of vent outlet (Tvent)] greater than [air temperature of defrosting outlet (Tdef)]. This relationship of the conventional air conditioning system 50 is different from the above-mentioned desired relationship required in the air conditioning system.
In order to overcome this problem and obtain the above-mentioned desired relationship, another type of conventional air conditioning system provided with a larger mixing area and additional unique dampers was developed. However, this type of conventional air conditioning has more complicated structure and a larger size than the previously described one.
Further, the conventional air conditioning system 50 of FIG. 8 has at least three dampers, such as the vent damper 74, the defrosting damper 76 and the foot damper 78, so as to produce various modes. Therefore, if the number of such movable components could be reduced, the reliability of the air conditioning system can be increased.
FIG. 9 is a partial plan view showing the evaporator 56 and the air inlet 54 of the conventional air conditioning system 50 of FIG. 8. As shown in FIG. 9, the air taken from the air inlet 54 is introduced into the evaporator 56 through a passage 54a having a uniform cross section. Therefore, the air flow is concentrated at the downstream side of the passage 54a, and the concentrated air flow is introduced into the evaporator 56 as shown by a symbol xe2x80x9cAxe2x80x9d in FIG. 9. As a result, the evaporator 56 can not attain its full cooling capability and problems may arise, such that dew is scattered due to the concentrated air flow and the air rates introduced into the right and left sides of the evaporator become different.
It is therefore an object of the present invention to provide an air conditioning system for a vehicle having a simple structure and a desired relationship of air temperatures in respective air outlets.
It is another object of the present invention to provide an air conditioning system for a vehicle wherein the number of movable components is reduced so as to increase the liability thereof
It is still another object of the present invention to provide an air conditioning system for a vehicle wherein air discharged from a blower flows uniformly into an evaporator so as to attain a high cooling capability.
The above objects are achieved according to the present invention by providing an air conditioning system comprising a casing, an evaporator mounted substantially in an upright position at a front portion within the casing, a heater core mounted substantially in an upright position at a rear side of the evaporator, a mixing area located at a rear side of the evaporator and an upper side of the heater core for mixing a first air bypassing the heater core with a second air flowing through the heater core, a partition plate for guiding the second air to the mixing area after the second air flows through the heater core, a foot passage defined by a rear portion of the casing and the partition plate, a defrosting passage communicating with a lower end of the foot passage and being provided along an outer surface of the casing, a vent outlet provided at a portion near the mixing area of the casing, a defrosting outlet provided at an upper end of the defrosting passage, a temperature controlling damper for controlling rates of the first air bypassing the heater core and the second air flowing through the heater core after the first and second airs flow through the evaporator so as to attain a predetermined final temperature of the air which is discharged into a passenger compartment of the vehicle, a vent damper for opening and closing the vent outlet, a foot damper for opening and closing the foot outlet, and a defrosting damper for opening and closing the defrosting outlet.
In a preferred embodiment of the present invention, the foot damper and the defrosting damper are a foot and defrosting damper for opening and closing both the foot outlet and the defrost outlet, the foot and defrosting damper being provided at a portion communicating with both the foot passage and the defrosting passage.
In another preferred embodiment of the present invention, the partition plate has a front portion facing substantially toward the front of the system.
In a still another preferred embodiment of the present invention, the vent outlet, the foot outlet and the defrosting outlet are provided along the casing such that, in the downstream area of the evaporator, the vent outlet is the nearest of the these three outlets to the evaporator, the defrost outlet is the farthest from the evaporator, and the foot outlet is located between the vent outlet and the defrosting outlet.
In still another embodiment of the present invention, the system further comprises a diffuser for guiding air discharged from a blower to the evaporator, the diffuser guiding the air from a lateral side of the evaporator to a front surface of the evaporator, and the diffuser having a cross section which becomes smaller toward the downstream side thereof.
The above object is also achieved according to another aspect of the present invention by providing an air conditioning system comprising a casing, an evaporator mounted in a front portion of the casing, and a diffuser for guiding air discharged from a blower to the evaporator, the diffuser guiding the air from a lateral side of the evaporator to a front surface of the evaporator, and the diffuser having a cross section which becomes smaller toward the downstream side thereof.
The above and other objects and features of the present invention will be apparent from the following description made with reference to the accompany drawings showing preferred embodiments of the present invention.